Dental implant system

ABSTRACT

An implant comprising two internal anti-rotational features. One anti-rotational feature is adapted to engage a driving tool, while the other anti-rotational feature is adapted to engage an abutment. An implant abutment system is provided with an angled abutment adapted to mate with one of the anti-rotational features. A second, straight abutment is adapted to engage with the other anti-rotational feature. An abutment is provided with resilient fingers to interface with the implant and provide tactile and audible feedback indicating when the abutment is properly seated. An abutment screw extends through the abutment and engages the implant bore distal of the stem of the abutment. The abutment screw limits axial movement of the abutment relative to the implant. A driving tool comprising one of at least retention structure and visual alignment indicia is provided to facilitate screwing the implant into a patient&#39;s bone.

RELATED APPLICATIONS

This application is based on U.S. Provisional Application No.60/450,541, filed Feb. 26, 2003; which is based on U.S. ProvisionalApplication No. 60/425,976, filed Nov. 13, 2002.

FIELD OF THE INVENTION

This invention relates to dental implants and abutments and relatedarticles.

BACKGROUND OF THE INVENTION

Single tooth restorations present the unique requirement that they mustbe supported non-rotationally on the underlying abutment. When aprepared natural tooth is the underlying abutment, this requirement ismet in the normal course of preparing the abutment with a non-circularcross-section. Likewise, when the underlying abutment is a post fittedonto an implant, this requirement is met by preparing the post with anoncircular cross-section. This latter scenario can be more complicateddue to the added connection between the implant and the abutment.

Typically, a dental implant is implanted into the bone of a patient'sjaw and comprises a socket, e.g., a bore, which is accessible throughthe overlying or surrounding gum tissue for receiving and supporting oneor more attachments or components which, in turn, are useful tofabricate and support the prosthodontic restoration. Dental implantprocedures can use a variety of implanting modalities, for example,blade, threaded implant, or smooth push-in implant. The presentinvention is not concerned with the implant modality that is used. Theinvention is, however, concerned with connections between implants andattachments, as well as with other matters.

With respect to connections used in implant systems, internal threads ofthe implant have been used to connect abutments having threaded stems.Rotational alignment is not, however, easily achieved using threadedconnections. Further, such a threaded bore, by itself, cannot generallyprovide rotational fixing. Rotationally fixing the prosthetic tooth tothe abutment, and rotationally fixing the abutment to the implant, mustbe accomplished to ensure that the prosthetic tooth is non-rotational inthe mouth of the patient after the restoration process is complete. Toimprove the likelihood that the implant will not exhibit movement, theimplant is typically allowed to undergo osseointegration prior to beingsubjected to normal loading.

To overcome the non-rotational deficiency between the implant andattachments, dental implants include an anti-rotational structure torestrain components attached to the implant against rotation relative tothe implant around the longitudinal axis through the bore. A commonstructure used to restrain rotation includes a male projection or afemale indentation located on or near the gingival surface of theimplant which is concentric with the opening into the bore. Thesedesigns are not, however, free of problems.

An inherent disadvantage of implant components is that their small sizemakes assembly difficult. Problems include the difficulty of properlypositioning abutments in implants. The relatively small size of thecomponents and tight working environment make it difficult to know whenan abutment is properly seated in an implant. Related problems includeabutments becoming loose due to the extreme forces incurred throughnormal chewing actions. Traditionally, axial retention has been achievedwith a screw threading through the abutment and attaching to theimplant. More recently, attempts have been made to eliminate the axialscrew by using snap-in abutments. These snap-in abutments generally areprovided with protrusions extending from the distal end of the stem ofthe abutment. Some of these snap-in designs are more successful thanothers. Practitioners have noted that some abutments used in thesescrewless systems become loose due to the large forces generated throughchewing. For some, the disadvantages associated with screwless abutmentsoutweigh any potential benefits.

These screwless abutments also exhibit unacceptable axial movement. Thisaxial movement can lead to damage of the abutment or the implant as aresult of misaligned forces and increased internal wear. The internalwear and misaligned forces lead to further unacceptable movement,inevitably requiring repair and replacement. In the mildest cases, thepatient is inconvenienced. In the more severe cases, where the patientwaits too long, infection and permanent bone and tissue damage occur.Thus, even systems that provide adequate connection must continually beimproved upon to reduce patient suffering, or worse.

The prior art has successfully addressed many problems. But not alldisadvantages have been overcome, and some solutions carry their owndisadvantages.

SUMMARY OF THE INVENTION

This invention, in particular, relates to dental implants and abutments.This invention also relates to rotation-limiting dental connectingmechanisms of the kind employing a non-round projection engaged in anon-round bore to connect two parts endwise in a fashion that limitsrelative rotation between the parts around their common longitudinalaxis. Some embodiments of the present invention are concerned withlimiting axial movement between endwise-connected dental implant systemparts. This present invention also concerns sensory feedback systemsindicative of connection conditions in dental implant systems.

An embodiment of the invention comprises a dental implant having aproximal end adapted to abut an abutment and an interior bore extendingdistally from the proximal end. As used herein, unless otherwiseindicated, a distal location is closer to or deeper in the bone than aproximal location. The implant is provided with a first anti-rotationcavity in the interior bore and a second anti-rotation cavity in theinterior bore. The first cavity comprises a first minor diameter and thesecond cavity comprises a second minor diameter no greater than thefirst minor diameter of the first cavity. Depending on the application,the second anti-rotation cavity is positioned distal of the firstanti-rotation cavity.

The implant may also be provided with an axial retention section distalof the first and second anti-rotation cavities. The axial retentionsection is adapted to mate with a device inserted into the interiorbore. The axial retention section comprises, for some embodiments, athreaded section in the interior bore that is adapted to mate with anabutment screw inserted into the interior bore. In an alternateembodiment, the axial retention section comprises a recess adapted toengage a resilient lip of a device inserted into the interior bore.Another embodiment uses both an abutment screw and a resilient featureto inhibit axial movement.

In another embodiment, the implant is provided with a first feedbackfeature distal of the first and second anti-rotation cavities. Thefeedback feature may, for example, comprise male geometry. In yetanother embodiment of the implant, the interior bore comprises afeedback feature and an axial retention feature. Anti-rotationalfeatures are, in some embodiments, provided in combination with afeedback feature and an axial retention feature.

Another embodiment of the invention is directed toward an implantsystem. A dental implant system in accordance with the inventioncomprises an implant, a first abutment, and a second abutment. Theimplant comprises a proximal end opening to a bore, a first internalanti-rotation cavity in the bore, and a second internal anti-rotationcavity in the bore, wherein the second internal anti-rotation cavity islocated distal of the first anti-rotation cavity.

The first abutment comprises a stem adapted to fit in the bore of theimplant. The stem comprises a first non-locking portion adapted to belocated in the first internal anti-rotation cavity withoutrotationally-lockingly engaging the first internal rotation cavity. Thestem further comprises a locking portion distal of the non-lockingportion. The locking portion is adapted to rotationally-lockingly engagethe second anti-rotation cavity.

By contrast, the second abutment comprises a stem having a lockingportion adapted to rotationally-lockingly engage the first anti-rotationcavity. The stem of the second abutment further comprises a non-lockingportion distal of the locking portion. The non-locking portion of thesecond abutment is adapted to be positioned in the second anti-rotationcavity without rotationally-lockingly engaging the first anti-rotationcavity.

An abutment cross-section need not, however, have the same configurationas that of an implant cross-section for the implant and the abutment tobe rotationally locked. For example, a 12-point hexagonal configurationcan lock with a 6-point hexagonal configuration. The two cross-sectionsshould, however, be adapted to be engaged such that relative rotation isrelatively small and, preferably, substantially eliminated.

The system may comprise one or both of the abutments. Further, in someembodiments, at least one of the abutments is an angled abutment. Theangled abutment, in some embodiments, comprises a locking sectionadapted to interface with at least one of the two or more anti-rotationcavities. Preferably, the abutment is adapted to be rotatable inincrements of 30° prior to fixedly engaging it with the implant. Thatis, the abutment is adapted for 30° indexing. One embodiment ofanti-rotational cavity adapted to provide 30° increment rotationcomprises a 12-point polygonal socket.

Another system of the invention comprises an implant having a firstinternal anti-rotation feature and a driving tool adapted to engage theimplant through the first internal anti-rotation feature. The system mayalso comprise an abutment adapted to engage the implant through a secondinternal anti-rotation feature of the implant.

An alternate implant system of the invention comprises an implantcomprising an interior bore and a feedback feature in the interior bore.A threaded section is positioned distal of the feedback feature. Thesystem further comprises an abutment adapted to be attached to theimplant.

The abutment comprises a post and a stem extending from the post. Thestem is adapted to fit in the interior bore. The stem comprises acomplementary feedback feature adapted to cooperate with the implantfeedback feature and provide feedback to a practitioner indicating whenthe abutment is properly seated. The complementary feedback feature may,for example, comprise male geometry. The feedback provided to thepractitioner may, for example, comprise tactile or audible output orboth tactile and audible output, such as when a resilient member snapsback to its non-deformed shape or position. The feedback system may,alternatively, or in combination with tactile and audible output,provide a visual indication concerning a seating condition of anabutment of coping structure.

An abutment screw is adapted to fit within a through-bore extendingthrough the post and stem of the abutment and retain to the abutment inthe implant. The abutment screw comprises a proximal end (e.g., thescrew head) adapted to interface with the abutment and a distal endadapted to engage the threaded section of the implant. More generally,the implant may be provided with an internal axial retention sectionadapted to engage an abutment retention shaft. The axial retention shaftengages an internal axial retention feature of the implant to limitaxial movement of the abutment relative to the implant.

Although the invention is directed toward individual components, such asthe implant, the abutment, the axial retention shaft, and to systemscomprising combinations thereof, other aspects and advantages of thepresent invention will be apparent to one of ordinary skill in the artfrom a review of the Applicants' teachings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B show a perspective view and top view of an implantcomprising two internal anti-rotation cavities and an angled abutmentpositioned for insertion into the implant.

FIG. 2 shows a cut-away sectional view of the implant and abutment shownin FIG. 1, but with the abutment seated in the implant. An abutmentscrew extends beyond the abutment stem and threadably engages theimplant.

FIG. 3 shows a side elevation view of the angled abutment shown in FIGS.1 and 2 and more clearly illustrates a locking portion and a non-lockingportion of a stem of the abutment.

FIGS. 4A and 4B show side elevation and cross-sectional views of astraight abutment comprising a stem having a locking portion and anon-locking portion, where the portions are in reverse order as comparedto those of the angled abutment shown in FIG. 3.

FIG. 5 shows a partial side elevation view with part of the implant cutaway to show the straight abutment illustrated in FIG. 4 seated in theimplant and axially secured with an abutment screw.

FIGS. 6A-6E illustrate an alternative embodiment of an implant.

FIGS. 7A and 7B illustrate an alternative embodiment of a straightabutment adapted to mate with the implant illustrated in FIGS. 6A-6E.

FIGS. 8A and 8B illustrate an alternative angled abutment adapted tomate with the implant illustrated in FIGS. 6A-6E.

FIGS. 9A-9C illustrate driving tools for driving the implant into thebone of the patient.

FIGS. 10A-10D illustrate an impression coping transfer cylinder adaptedto engage an implant, such as, for example, the implant illustrated inFIGS. 1A and 1B.

FIGS. 11A and 11B illustrate an impression coping transfer screwsuitable for use with the impression coping transfer cylinderillustrated in FIGS. 10A-10D.

FIGS. 12A and 12B illustrate a pickup screw suitable for use with theimpression coping transfer cylinder illustrated in FIGS. 10A-10D.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

FIGS. 1 and 2 illustrate an implant 10 adapted to be screwed into thebone of a patient and an abutment 40 adapted to be connected to theimplant 10. The implant 10 comprises a proximal end 12 including a table14 adapted to abut the abutment 40. The implant 10 comprises a distalend 16 opposite the proximal end 12 and at least one thread 18 disposedtherebetween for screwing the implant 10 into the bone of a patient. Aninterior bore 20 extends distally from the proximal end 12 toward thedistal end 16. The interior bore 20 comprises a first anti-rotationcavity 22 and a second anti-rotation cavity 24 distal of the firstanti-rotation cavity 22.

In FIG. 1, the two cavities 22 and 24 are separate, distinct andslightly spaced apart, and are connected with a tapered section. Otherarrangements, however, are equally suitable, such as, for example, wherethe cavities are adjacent and step-wise connected, or spaced apart andconnected by one or more cavities.

Focusing on FIG. 1B, an end view of the implant 10 is shown. In theembodiment illustrated in FIG. 1B, the first anti-rotation cavity ofimplant 10 comprises a hexagonal socket 26. The hexagonal socket 26comprises a plurality of obtuse interior angles. By contrast, the secondanti-rotation cavity 24 comprises a 12-point polygonal socket 28including a plurality of obtuse interior angles. The hexagonal socket 26comprises a minor diameter 30 and the 12-point polygonal socket 28comprises a minor diameter 32. The minor diameter 32 is less than theminor diameter 30 of the hexagonal socket 26. And, the major diameter ofthe hexagonal socket 26 is larger than the minor diameter 32 of the12-point polygonal socket 28. In one embodiment, the minor diameter 30is approximately 0.11 inch and the minor diameter 32 is approximately0.09 inch. For some embodiments, the difference between the major andminor diameters is in the range of 0.0005 and 0.1 inch. As used herein,the term minor diameter refers to the diameter of the largest cylindersized to fit within a polygonal cavity, whereas the term major diameteris the diameter of a cylinder contacting the external points at cornersof such a cavity.

For some applications, at least one of the anti-rotation cavities 22 and24 is adapted to mate with a conventional driving tool, for example, atool with a working end comprising a square, a pentagon, a hexagon, anoctagon, etc. Preferably, at least the other cavity is adapted to matewith an abutment stem having a predetermined shape. Some tools aredescribed in FIG. 9.

In one conventional implant system, an implant comprises an externalhexagon, i.e., a hexagonal projection, for engaging a driving tool. Thedriving tool applies relatively significant amounts of torque to theexternal hexagonal projection to screw the implant into the patient'sbone. After the implant is screwed into place and healing has occurred,an abutment is mated with the external hexagonal projection and seatedon the implant. Unfortunately, the significant amount of torque appliedto the hexagonal projection often mars and distorts the hexagonalconfiguration. This distortion can, in some applications, result inplay, or wiggle-room, between the implant and the abutment.

To overcome this distortion-related problem, the implant 10 has beenprovided with the first and second anti-rotation cavities 22 and 24. Theimplant 10 may, for example, be driven with a driving tool through thefirst anti-rotation cavity 22. The abutment 40 can then be mated withthe second anti-rotation cavity 24, which has not been subjected todriving torques as was the first anti-rotation cavity 22. The secondanti-rotation cavity 24 is in pristine condition, enabling a tight fitto occur between the abutment 40 and the implant 10. Although theinvention is not limited to internal anti-rotational features, anadvantage of internal anti-rotation cavities, over external projections,is that the cavity can generally be longer (deeper) than would bepossible with an external feature. The longer length provides greatersurface area for engaging a driving tool. Thus, there is a smallerchance of damaging the implant during installation.

The cavities illustrated in FIG. 1B are generally straight and compriseperimeters generally parallel with a longitudinal axis. Other shapes,such as frusto-conical, are appropriate for different applications. Forsuch shapes, analogues of the terms major and minor diameter areapplicable.

Turning to FIG. 2, which illustrates a partial sectional view, theabutment 40 is shown abutting, i.e., seated on, the implant 10. Theinterior bore 20 of the implant 10 comprises a feedback feature 34 forinterfacing with the abutment 40 and providing feedback to apractitioner indicating when the abutment 40 is properly seated withinthe implant. The feedback feature 34 may, for example, comprise malegeometry. Distal of the implant feedback feature 34 is an axialretention feature 36 embodied in the form of a plurality of threads. Anabutment screw 70 extends through the abutment 40 and interfaces withthe threads of the axial retention feature 36 to limit axial movement ofthe abutment.

Referring to FIGS. 1 and 2, the abutment 40 comprises a post 42 and astem 44 extending in a relative downward direction from the post 42. Thestem 44 comprises a non-locking portion 46 adapted to be positioned inthe first anti-rotation cavity 22 when the abutment 40 is seated in theimplant 10. The stem 44 further comprises a locking portion 48 adaptedto be positioned in the second anti-rotation cavity 24 when the abutment40 is positioned in the implant 10. The locking portion 48 is adapted torotationally-lockingly engage the second anti-rotation cavity 24,wherein the abutment 40 is prevented from rotating relative to theimplant 10.

For some applications, it is desirable to be able to increment theangled abutment 40 in steps to achieve the proper functional andcosmetic alignment of a prosthetic ultimately affixed to the post 42,i.e., the abutment may be indexed. Accordingly, the locking portion 48and the second anti-rotation cavity 24 are adapted to provide apredetermined minimum rotational increment. The illustrated embodimenthas a minimum rotational increment of 30° due to the 12-point shape.Once the abutment 40 is rotationally aligned, the practitioner can applypressure to seat the abutment 40, while being sensitive to feedbackindicative of the abutment's seating status.

The polygonal shape is not required to have actual points. Other formsof interface, for example, indentations and projections, are suitable tolimit rotation between the implant 10 and the abutment 40. Furthermore,shapes other than polygons are suitable for limiting rotation betweenthe components. The actual rotational increment size will depend, atleast in part, on the anti-rotation feature in the second cavity 24 andthe shape of the locking portion 48.

Turning briefly to FIG. 3, to rotationally lock the locking portion 48to the implant 10, the locking portion 48 comprises a major diameter 50greater than the minor diameter 32 of the second anti-rotation cavity24. The major diameter 50 is greater than the minor diameter 32 so theprojections and indentations engage to limit, or eliminate, rotationbetween the implant 10 and the abutment 40. In contrast, the non-lockingportion 46 comprises a major diameter 52 smaller than or approximatelyequal to the minor diameter 30 of the first anti-rotation cavity 22.Thus, the non-locking portion 46 of the abutment 40 does notrotationally engage the implant 10.

Returning to FIG. 2, the abutment 40 comprises a feedback feature 54adapted to engage the implant 10 as the abutment 40 is being seated andto provide an indication to the practitioner when the abutment 40 isproperly seated. The feedback features 34 (of the implant 10) and 54 (ofthe abutment 40) may collectively comprise one or more resilient membersadapted to deform during the seating process and reform when theabutment is properly seated. With reference to FIGS. 1 and 3, thefeedback feature 54 of the abutment 40 comprises a plurality ofresilient fingers 56 located at the distal end of the stem 44.

The feedback system may be a system adapted to provide only tactilefeedback, or only audible feedback or both tactile and audible feedback.A system is considered to provide feedback when the sensory output is ofa sufficient level so as to be sensed by a practitioner without thepractitioner taking extraordinary steps to receive the feedback.Generally, use of tactile feedback and audible feedback, alone or incombination, is desirable in many applications due to the relativesimplicity of such systems and the advantages of such systems overcurrent verification practices.

Verification techniques involve additional steps, typically takenimmediately after the practitioner performs the abutment-seating steps,that often use additional equipment. Current verification practicestypically involve the use of radiographic equipment, e.g., an X-ray. Useof radiographic equipment is both relatively costly and time-consuming.The practitioner must adjust the equipment to take a proper image, andtypically step out of the room to snap the image. The patient is alsoexposed to another dose of radiation. Such verification systems are bothcostly and time-consuming. In contrast, a feedback system does not havethe attendant costs and delays of verification systems. The feedbacksystem of the present invention operates, in a practical sense,contemporaneous with the seating process. A verification processinvolves identifiable steps separate from those required to seat anabutment.

In some embodiments, the abutment 40 is adapted to be axially-restrainedin the bore 20 without additional components. In essence, the abutment40 is autonomously axially-restrained when seated. The stem 44 of theabutment 40 comprises axial retention features adapted to interface withaxial retention features in the abutment interior bore 20. In theillustrated embodiment, the implant feedback feature 34 and the abutmentfeature 54 also have retention capability. The axial retention feature54 comprises the plurality of fingers 56 that are adapted to provideboth feedback and retention capabilities.

Other structures are suitable for providing one or both axial retentionand feedback capabilities. In some embodiments, including somecomprising resilient members providing both retention and feedback, anadditional axial retention structure is required, or at least desirable.Such additional axial retention structure may be integral with one orboth of the abutment 40 and the implant 10. Alternatively, the structuremay be separate, but coupled to and relatively fixed, with respect toone of either the abutment or the implant. Furthermore, separateadditional axial retention structures need not be relatively fixed toeither one of the abutment or the implant. For example, the separateadditional retention structure may also be provided as an abutmentretention shaft that interfaces with one or both the abutment 40 and theimplant 10, yet is separable from both. One example of an abutmentretention shaft is the abutment screw 70 illustrated in FIG. 2.

In FIG. 2, a through-bore 60 extends through the post 42 and the stem 44to allow the abutment screw 70 to be inserted therein. The through-bore60 comprises a first diameter 62 and a second diameter 64 distal of thefirst diameter 62 and smaller than the first diameter 62. The abutmentscrew 70 is inserted into the through-bore 60 to threadably engage thethreads 36 of the implant 10.

In FIG. 2, the abutment screw 70 comprises a screw head 72 adapted tocouple with a driving tool, for example, an Allen wrench. Other abutmentscrew head driving structure, e.g., a square driver, a flat headscrewdriver, a Phillips screwdriver, will be suitable. A shank 74extends distally from the head 72 to a distal threaded end 76. The head72 comprises a first diameter, and the shank 74 comprises a seconddiameter smaller than the head diameter. The head diameter is preferablylarger than the through-bore 60 second diameter 64 to prevent theabutment from moving axially past the screw head 72. Thus, after theabutment screw 70 threadably engages the implant 10, the screw 70 actsto retain the abutment 40 in the implant 10.

The system may also comprise a straight abutment 90, for example,illustrated in FIG. 4, which is compatible with the implant 10. Thestraight abutment 90 comprises a post 92 and a stem 94. The stem 94comprises a non-locking portion 96 and a locking portion 98. In contrastto the angled abutment 40, the non-locking portion 96 is distal of thelocking portion 98.

FIG. 5 is a side elevation view showing the straight abutment 90 seatedin the implant 10. Part of the implant 10 is cut away to betterillustrate the straight abutment 90 and part of the abutment screw 70,which acts to limit axial movement of the abutment. The locking portion98 is adapted to rotationally-lockingly engage the first anti-rotationcavity 22 when the abutment 90 is positioned in the implant 10. Thenon-locking portion 96 does not so engage the second anti-rotationcavity 24.

To avoid rotational lock between the implant 10 and the second cavity24, the non-locking portion 96 has a major diameter 100 (FIG. 4) nolarger than the minor diameter 32 of the second anti-rotation cavity 24.To provide rotational engagement between the stem 94 and the implant 10,the locking portion 98 has a major diameter 102 (FIG. 4) that is largerthan the minimum diameter 30 of the first anti-rotation cavity 22. Thus,in embodiments illustrated in FIGS. 1-5, the angled abutment 40rotationally engages the implant 10 through the second anti-rotationcavity 24, whereas the straight abutment 90 rotationally engages theimplant 10 through the first anti-rotation cavity 22.

The first anti-rotation cavity 22 may comprise a configuration includinginterior acute angles while the second anti-rotation cavity 24 comprisesa configuration including interior obtuse angles. Furthermore, bothcavities may be provided with the same type of configuration, but ofdiffering diameters. Additionally, the straight abutment 90 may beadapted to engage the implant 10 through the second anti-rotation cavity24, whereas the angled abutment 90 is adapted to engage the implant 10through the first anti-rotation cavity 22.

To facilitate compatibility among components, a system in accordancewith principles of the invention may comprise an implant having oneinternal anti-rotation feature for engaging both straight and angledabutments and another internal anti-rotation feature for engaging adriving tool. The one internal anti-rotation feature may be adapted toengage the driving tool as well as the abutments. Similarly, the otheranti-rotation feature may be adapted to engage multiple abutment stemtypes as well as the driving tool. And although the invention isprimarily described with respect to implants having two internalfeatures, principles of the invention are not so limited. An implant maybe provided with a single internal anti-rotation feature, with a singleexternal anti-rotation feature, with two or more internal features, ortwo or more external features, or various combinations.

FIG. 6A illustrates a side view of an implant 10′. FIG. 6B is a sectionview taken along such line 6B-6B of the implant 10′ in FIG. 6A. FIG. 6Cis an end view looking down the bore of the implant 10′ The implant 10′is generally similar to the implant 10, except that the interior bore 20of the implant 10′ comprises a recess 110 adapted to retain a toroidalflexible member, such as a toroidal spring, that may interface with anabutment as the abutment is seated. The toroidal flexible memberprovides feedback to the practitioner indicating when the abutment isproperly seated. The toroidal flexible member may, for example, comprisemale geometry, for example, a round tube formed into a toroid. FIG. 6Dillustrates a straight abutment 90′ seated in the implant 10′.

FIGS. 7 and 8 illustrate abutments adapted to interface with the implant10′ shown in FIGS. 6. FIG. 7A is a side elevation view of a straightabutment 90′. FIG. 7B is a section view along section line 7B-7B of FIG.7A. FIG. 8A is a side elevation view of an angled abutment 40′. FIG. 8Bis a section view along section line 8B-8B of FIG. 8A. The stems of boththe straight abutment 90′ and the angled abutment 40′ comprise acomplementary recess 112. The recess 112 is positioned to be adjacentthe recess 110 in the interior bore 20 of the implant 10′ when theabutment is seated. The recess 110 and the complementary recess 112define an area in which a toroidal ring would rest when the abutment isseated.

With reference to FIGS. 6B and 6D, the implant 10′ includes a secondgroove 114 for providing feedback. The second groove 114 is also usefulin the implant 10 of FIGS. 1-5. The second groove 114 is useful forretaining a driving tool or other component, for example, an impressioncoping, in operable contact with the implant 10′. In one embodiment ofthe embodiment illustrated in FIG. 6, the implant 10′ has length L that,for some applications, is approximately between 0.3 inch and 0.9 inch.The first and second anti-rotation cavities 26 and 28 extend into thebore a combined depth of approximately 0.1 to 0.2 inch. A finger passage115 extends to a depth of approximately 0.1 to 0.3 inch. The secondgroove 114 has a mid-line positioned approximately 0.01 to 0.2 inch fromthe table 14. The recess 110, beginning at a depth of approximately 0.1to 0.3 inch, has a width of approximately 0.01 to 0.2 inch. Thesedimensions are illustrative and suitable for particular applications,but are not the only suitable dimensions for a dental implant inaccordance with the Applicants' teachings. A toroidal spring 116 ispositioned in the area defined by the recess 110 and the complementaryrecess 112. The toroidal spring 116 acts against the resilient member 54to apply a retention force to the straight abutment 90′.

With reference to FIGS. 6B, 6D, 6E, 7A and 7B, to reduce stress, theimplant 10′ comprises a counterbore 120 to receive a base 122 of theabutment 90′. In FIG. 6E, part of the abutment 90′ is removed to aidillustration. The base 122 is positioned between a margin 124 and thelocking portion 98 that mates with the first anti-rotation cavity 26.Counterbore 120 has a diameter of approximately 0.10 to 0.15 inch and adepth of approximately 0.01 inch. To reduce point stresses, thecounterbore 120 comprises a chamfer 126 and a fillet 128 with dimensionsapproximately 0.001 to 0.01 inch. The base 122 comprises a chamfer 130corresponding to the fillet 128. The chamfers 130 and 126 togetherfacilitate placing the abutment 90′ into the implant 10′.

FIG. 9A is a perspective view of one type of a driving tool 200 adaptedto mate with the second anti-rotation cavity 28 of the implant 10′ orthe implant 10. The driving tool 200 comprises a first end 202comprising a 12-point polygonal male geometry 204 adapted to mate withthe second anti-rotation cavity 28. An opposing end 206 comprises ahandle 208 to facilitate gripping the driving tool 200.

FIG. 9B illustrates another type of driving tool 220 adapted to matewith the first anti-rotation cavity 26 of the implant 10′ or the implant10. The driving tool 220 comprises a first end 222, on a working end,that is adapted to fit within the bore 20 of the implant 10′. The firstend comprises a resilient ring, such as an O-ring 224, that couples withthe second recess 114 of the implant 10′ to help retain the driving tool220 in proper engagement with the implant 10′. The working end 222 ofthe driving tool 220 comprises a hexagonal male geometry driving portion226 adapted to mate with the anti-rotation cavity 26. The diameterdistal of the O-ring 224 is sized to fit within the second anti-rotationcavity 28. The working end 222 includes a stop 228 that abuts againstthe table 14 of the implant 10′ when the driving tool 220 is properlyseated. The O-ring 224 and the stop 228 cooperate to reduce, andpreferably eliminate, unwanted axially motion of the drive tool 220relative to the implant 10′. The O-ring 224 may be adapted to providetactile or audible, or both tactile and audible, feedback indicative ofa seating condition of the driving tool. The stop 228 provides at leasta visual feedback.

An alignment portion 230 of the working end 222 comprises a hexagonalshape aligned with the hexagonal driving portion 226. The alignmentportion 230 facilitates aligning the driving portion 226 with the firstanti-rotation cavity 26 while the driving tool 220 is being coupled withthe implant 10′. After the tool 220 is mated with the implant 10′, thealignment portion 230 provides a visual indication as to how the implant10′ anti-rotation cavity 26 is aligned in the mouth of the patient,e.g., the rotational alignment of the implant 10′. The illustratedalignment portion 226 comprises male alignment geometry in the form ofthe hexagonal shape. Alternative to, or in combination with, the malealignment geometry, the working end 230 may be provided with visualalignment indicia, such as lines running along the length of the workingend 230.

The driving tool 220 may be provided with a handle 232 to facilitategripping the driving tool 220. The handle 232 is not required, however,as the alignment portion 230 may comprise sufficient structure to aidgripping the driving tool 220.

FIG. 9C illustrates a driving tool 240 that is similar to the drivingtool 220 illustrated in FIG. 9B. The driving tool 240 comprises ahexagonal driving portion 226′ and a stop 228′ and an interfacestructure 224′ that facilitates interfacing the driving tool 240 withthe bore of an implant. And, the driving tool 240 comprises an iso-latch242 that is to couple the driving tool 240 to a power driving mechanism.

FIG. 10A illustrates a side elevation view of a transfer impressioncoping cylinder 300. The impression coping comprises an impression end310 for interfacing with impression material and an implant interfaceend 320 for interfacing with an implant. The implant interface end 320comprises an anti-rotation section 322, e.g., a hexagonal extension, anda resilient interface 324 to temporarily hold the transfer cylinder 300in an implant until a screw secures the cylinder to the implant. FIG.10B illustrates an end view of the transfer cylinder 300 showing theimplant interface end 320. FIG. 10C illustrates an end view of theimpression end 310. FIG. 10D illustrates a section view taken alongsection line 10D-10D of FIG. 10B. The cylinder 300 includes athrough-bore 330 with a reduced cross-section portion 332.

FIG. 11A illustrates an impression coping transfer screw 350 suitablefor use with the transfer cylinder 300. The transfer screw 350 comprisesa shaft 352 that is sized to extend through the through-bore 330 of thetransfer cylinder 330 and connect to the implant via threads 360. FIG.11B is an end view of the transfer screw 350.

FIG. 12A illustrates a twist lock pickup impression screw 380 suitablefor use with the transfer cylinder 300. The transfer screw 380 comprisesa shaft 382 that is sized to extend through the through-bore 330 of thetransfer cylinder 330 and connect to the implant via threads 390. FIG.12B is an end view of the transfer screw 380.

The impression coping components illustrated in FIGS. 10-12 aredescribed in further detail in U.S. Pat. No. 5,685,715, which isincorporated herein by reference in its entirety. Such an impressioncoping can be prepackaged and delivered to the clinician with theimplant such that the coping serves as a mount that receives torque forinstalling the implant into the bone of the patient. Consequently, thepresent invention contemplates using one of the anti-rotational featuresof the implant for engaging the mount, rather than, for example, one ofthe driving tools shown in FIG. 9, and another anti-rotational featurefor engaging an abutment or coping if the coping is not used as a mount.

One method for improving connectivity in accordance with the inventionincludes coupling an abutment to an implant positioned in a patient, andsensing a tactile feedback associated with seating the abutment.Subsequent to sensing the tactile feedback, the implant is engaged withretention structure to resist axial movement of the abutment relative tothe implant. The retention structure may be rotated while engaging athread and allowed to move deeper into the implant as the retentionstructure is rotated.

The retention structure may be engaged with the implant to limit axialmovement of the abutment relative to the implant, but allow somemovement of the abutment when a dislodging force is applied to theabutment. For example, the retention structure may threadably engage theimplant, but prior to fully screwing the structure down, the abutmentcan be unseated if a sufficient force is applied. In this manner, apractitioner, e.g., a dentist, can apply a test force insufficient todislodge the abutment but sufficient to verify that the abutment has notbecome loose. This avoids problems associated with applying forces,through the retention structure, to an abutment that has becomemisaligned subsequent to having been seated.

To reduce unwanted rotation between an implant and an abutment, a torqueis applied to a first internal anti-rotation feature of the implant toinsert the implant deeper into a bone. Subsequent to applying the torqueto the first internal anti-rotation feature, an abutment is engaged witha second internal anti-rotation feature of the implant. Such a processallows the abutment to engage a pristine feature, one not damaged whileinserting the implant into the patient.

Another advantage of using an implant that has two internalanti-rotation features is that a suitable abutment can be selected froma plurality of abutments and the selection can be based, at least inpart, upon prevailing conditions in the patient's mouth. Generally, thisuse of an implant having two or more anti-rotation features results in awider assortment of abutments that can be mated to the implant than canbe mated to an implant comprising only one anti-rotation feature. Whileeach abutment type is theoretically available with any stem type, asuitable abutment is not as readily available as a practitioner wouldlike. A suitable abutment has a stem that, in fact, can be mated to theosseointegrated implant and is suitable for other prevailing conditionsin the patient's mouth. To reduce problems associated with not having asuitable abutment, a practitioner installs an implant comprising twointernal anti-rotation features. The practitioner can then be fairlyconfident that when it comes time to attaching an abutment, a suitableabutment having a stem adapted to engage at least one of the featureswill be available.

The invention clearly reduces connectivity problems and other problemsencountered in the field of dental implants. Applying principles of theinvention to dental restoration processes yields improved results. Thelikelihood of a suitable abutment being available, when needed, isincreased, while reducing the amount of planning required. And, costsmay also be reduced by eliminating or reducing the need to useverification equipment, such as radio-graphic equipment, during therestoration process.

Use of terms such as first, second, up, below, etc., are for conveniencein describing the illustrated embodiments and such use is not intendedto limit the variety of embodiments of the invention. Similar featuresare identified throughout with similar numbers to aid understanding butnot to indicate such features are required to be identical among thevarious embodiments.

The foregoing description of the invention is illustrative andexplanatory. Various modifications and alterations to the embodimentsdisclosed herein will be apparent to those skilled in the art in view ofthis disclosure. It is intended that all such variations andmodifications fall within the spirit and scope of this invention asclaimed.

1. A dental implant, comprising: a proximal end adapted to abut anabutment; an interior bore extending distally from the proximal end; afirst anti-rotation cavity having a non-round shape in the interior boreand comprising a first minor diameter, the first anti-rotation cavity isa polygonal shape and is adapted to mate with a driving tool; and asecond anti-rotation cavity having a non-round shape and spaced awayfrom the first anti-rotation cavity in the interior bore and comprisinga second minor diameter, the first minor diameter being greater than thesecond minor diameter, the second anti-rotation cavity defining apolygonal shape comprising a plurality of obtuse angles.
 2. The implantof claim 1, wherein the polygonal shape of the second anti-rotationcavity comprises at least six angles, including the plurality of obtuseangles.
 3. The implant of claim 1, further including a first axialretention section in the interior bore distal of the secondanti-rotation cavity, the first axial retention section having apredetermined configuration adapted to couple with a device insertedinto the interior bore.
 4. The implant of claim 3, wherein the firstaxial retention section comprises a recess adapted to engage a resilientlip of a device inserted into the interior bore.
 5. The implant of claim4, comprising a second axial retention section in the interior boredistal of the first axial retention section, wherein the second axialretention section comprises a threaded section comprising a majordiameter not greater than the second minor diameter of the secondanti-rotation cavity.
 6. The implant of claim 3, wherein the first axialretention section comprises a threaded section.
 7. A dental implantsystem comprising the dental implant of claim 1 and further comprising:the driving tool adapted to engage the first anti-rotation cavity; andan abutment adapted to engage the second anti-rotation cavity.
 8. Adental implant, comprising: a proximal end; an interior bore extendingdistally from the proximal end; a first anti-rotational feature thatdefines a non-round cross-sectional shape in the interior bore; and asecond anti-rotational feature that defines a non-round cross-sectionalshape in the interior bore, wherein the second anti-rotation feature ispositioned distal of the first anti-rotational feature to providerotational resistance independent of the first anti-rotational feature,and the second anti-rotational feature has a smaller cross-sectionaldimension than a cross-sectional dimension of the first anti-rotationalfeature.
 9. The dental implant of claim 8, wherein the firstanti-rotational feature defines a polygonal shape comprising a pluralityof obtuse interior angles.
 10. The dental implant of claim 9, whereinthe plurality of obtuse interior angles of the polygonal shape of thefirst anti-rotational feature comprises at least six angles.
 11. Thedental implant of claim 9, wherein the second anti-rotational featuredefines a polygonal shape.
 12. The dental implant of claim 8, whereinthe first anti-rotational feature defines a polygonal shape.
 13. Thedental implant of claim 12, wherein the second anti-rotational featuredefines a polygonal shape comprising a plurality of obtuse interiorangles.
 14. The dental implant of claim 13, wherein the polygonal shapeof the second anti-rotational feature comprises at least six angles,including the plurality of obtuse interior angles.
 15. The dentalimplant of claim 8, wherein one of the first and second anti-rotationalfeatures is adapted to mate with an abutment and the other of the firstand second anti-rotational features is adapted to mate with a drivingtool.
 16. The dental implant of claim 8, wherein one of the first andsecond anti-rotational features is adapted to couple with an abutmentand to enable relative rotational adjustments to be made by a minimumrotational increment of 30°, whereby the abutment may be rotationallyaligned relative to the implant before seating the abutment in theimplant.
 17. The dental implant of claim 8, wherein the firstanti-rotational feature is adapted to allow a first minimumcircumferential incremental adjustment, and the second anti-rotationalfeature is adapted to provide a second minimum circumferentialincremental adjustment greater than the first minimum circumferentialincremental adjustment.
 18. The dental implant of claim 8, wherein thefirst anti-rotational feature and the second anti-rotational featurehave different polygonal shapes.
 19. The dental implant of claim 8,wherein at least one of the first and second anti-rotational features issymmetric about a longitudinal axis running through the interior bore.20. The dental implant of claim 8, further including an axial-retentivefeature for mating with a resilient feature of an abutment, theaxial-retentive feature being distal of the second anti-rotationalfeature.
 21. The dental implant of claim 20, further including athreaded section located distally of the axial-retentive feature.
 22. Adental implant system, comprising: (a) an implant comprising: a proximalend opening to a bore, a first internal anti-rotation feature having apolygonal shape in the bore, and a second internal anti-rotation featurehaving a polygonal shape in the bore distal of the first anti-rotationalfeature, the second internal anti-rotation feature having a smallerminor diameter than a minor diameter of the first internal anti-rotationfeature; (b) a first abutment comprising a stem adapted to fit in thebore of the implant, wherein the stem comprises: a non-locking portionadapted to be located in the first internal anti-rotation featurewithout rotationally-lockingly engaging the first internal anti-rotationfeature, and a locking portion distal of the non-locking portion andadapted to rotationally-lockingly engage the second anti-rotationfeature; and (c) a second abutment comprising a stem adapted to fit inthe bore of the implant, wherein the stem comprises: a locking portionadapted to rotationally-lockingly engage the first anti-rotation featureof the implant.
 23. The system of claim 22, wherein the stem of thesecond abutment comprises a non-locking portion distal of the lockingportion and adapted to be positioned in the second anti-rotation featurewithout rotationally-lockingly engaging the second anti-rotationfeature.
 24. The system of claim 22, comprising a driving tool adaptedto be selectively engaged with either the first feature or the secondfeature.
 25. A dental implant system, comprising: (a) an implantcomprising: an interior bore, a first internal anti-rotation sectionhaving a non-round shape, and a second internal anti-rotation sectionhaving a non-round shape, the second internal anti-rotation sectionbeing spaced away from the first internal anti-rotation section, thefirst internal anti-rotation section comprises a first minimum diameterand the second internal anti-rotation section comprises a second minimumdiameter less than the first minimum diameter; and (b) an abutmentcomprising a stem adapted to fit in the bore and comprising: a firstsection adapted to be positioned in the first internal anti-rotationsection of the implant, and a second section adapted to be positioned inthe second internal anti-rotation section of the implant, wherein onlyone of either the first section of the stem or the second section of thestem rotationally-lockingly engages the implant when the abutment isseated.
 26. The implant system of claim 25, wherein the first section ofthe stem comprises a first major diameter and the second section of thestem comprises a second major diameter less than the first majordiameter.
 27. The implant system of claim 26, wherein the first majordiameter of the first section of the stem is not greater than the firstminimum diameter of the first anti-rotation section of the implant. 28.The implant system of claim 26, wherein the second major diameter of thesecond section of the stem is not greater than the second minimumdiameter of the second anti-rotation section of the implant.
 29. Theimplant system of claim 25, comprising a driving tool adapted torotationally-lockingly engage the first internal anti-rotation sectionof the implant, wherein the abutment is adapted torotationally-lockingly engage the second internal anti-rotation sectionof the implant.
 30. A dental implant system, comprising: (a) an implantcomprising: an interior bore, a first internal anti-rotation sectionhaving a hexagonal shape and a first minor diameter, and a secondinternal anti-rotation section having a hexagonal shape and a secondminor diameter smaller than the first minor diameter, the secondinternal anti-rotation section being distal of the first internalanti-rotation section; and (b) an abutment comprising a stem adapted tofit in the bore and comprising: a first section adapted to be positionedin the first internal anti-rotation section of the implant, and a secondsection distinct from the first section of the abutment adapted to bepositioned in the second internal anti-rotation section of the implant,wherein one or more of the first and second sections of the stemrotationally-lockingly engages the implant when the abutment is seated.31. A dental process, comprising: selecting a suitable abutment from aplurality of abutments; and coupling the suitable abutment to one of twointernal anti-rotation features of an implant that is installed within apatent's mouth, the two internal anti-rotation features having apolygonal shape and different diameters.
 32. The process of claim 31,comprising selecting the suitable abutment based at least in part uponprevailing conditions in the patient's mouth.
 33. The process of claim32, comprising inserting the implant into the patient's mouth prior toselecting the suitable abutment.
 34. An implant system, comprising: animplant including a bore, a first anti-rotational feature comprising afirst anti-rotational cavity having a polygonal shape and located in thebore, and a second anti-rotational feature comprising a secondanti-rotational cavity having a polygonal shape and located in the boredistinct from the first anti-rotational cavity, wherein the firstanti-rotation feature has a different diameter than the secondanti-rotation feature; a mount adapted to couple to the firstanti-rotational feature to transfer torque to the implant to install theimplant in a patient; and an abutment adapted to couple to the secondanti-rotational feature.
 35. The system of claim 34, wherein the mountis prepackaged attached to the implant, whereby the practitioner isprovided with the mount already coupled to the implant.
 36. The systemof claim 34, wherein the mount is an impression coping.
 37. A dentalimplant, comprising: a proximal end adapted to abut an abutment; aninterior bore extending distally from the proximal end; a firstanti-rotation cavity in the interior bore defining a polygonal shape andbeing adapted to mate with a driving tool, the first anti-rotationcavity comprising a first minor diameter; and a second anti-rotationcavity in the interior bore defining a polygonal shape comprising aplurality of obtuse angles, the second anti-rotation cavity comprising asecond minor diameter, wherein the first minor diameter is greater thanthe second minor diameter.